The object of the invention is a process for the conveyance of beverage packings made of metal, glass, paper, cardboard and/or plastic, particularly in this case polyethylene terephthalate or polycarbonate, whereby the lubricant concentrate according to the invention, respectively its aqueous use solution, is applied.
Presently beverages are being sold in several different containers. Thus, beverages are offered in glass bottles, plastic bottles, plastic containers, boxes, wax cartons, etc. In the filling works these containers have to be transported during filling to several stations. Generally this occurs by means of feed or conveyance installations, which usually consist of stainless steel, insofar as these containers concern glass containers or consist of plastic materials like polypropylene or certain polyacetates, insofar as these containers concern other than glass bottles or glass containers. Following hereafter, such installations are referred to as feed and conveyance installations.
During filling and transport of the mentioned containers sometimes a turning over or a blocking of the containers may occur, while the conveyor belts are running further without hindrance. Especially in this case a sufficient lubrication of the conveyor belts is required in order that the belt can move forward without hindrance even when the containers on the belt cannot move forward during some time.
For this purpose it is required, as already mentioned before, to lubricate and to clean the parts of the feed and conveyance installations, which come into contact with the beverage containers, sufficiently. If the conveyance installations are not lubricated sufficiently this can, on the one hand, lead to the falling down of the containers, or on the other hand, have the result that they do not stop, although the respective filling up, cleaning or labelling station has already been reached. Both kinds of malfunctions can lead to longer standing times of the conveyance installations and to considerable loss of capacity.
It should also particularly be watched in the food industry that, besides the lubricating and cleaning action, the chain lubricating means have a sufficiently disinfecting, especially biostatic, action. In principle it should be decided that germ promoting use solutions of lubricant con- centrates should not be used.
Presently the applied chain lubricants can in principle be divided into three main groups:
1. Lubricants on basis of soap, PA1 2. Lubricants on basis of fatty amines and PA1 3. Lubricants on basis of phosphate esters. PA1 D1=DE 36 31 953 A1; PA1 D2=EP 0 372628B1; PA1 D3=EP 0 8384282B1; PA1 D4=WO 94/03562; and PA1 D5=WO 95/19412. PA1 (i) one or more amines; PA1 (ii) one or more ether carboxylic acid compounds with the general formula I EQU R.sup.1 -(O(CH.sub.2).sub.m).sub.n OCH.sub.2 COO.sup.- M.sup.+(I), PA1 R.sup.1 is a saturated, linear or branched C.sub.1 -C.sub.22 alkyl group, a mono or polyunsaturated, linear or branched, alkenyl or alkinyl group with 2 to 22 carbon atoms or possibly a mono or poly C.sub.1 -C.sub.22 alkyl or C.sub.2 -C.sub.22 alkenyl or alkinyl substituted aryl group, PA1 m is 2 or 3, PA1 n is a positive number in the range of 1 to 30, and PA1 M is hydrogen or an alkali metal; PA1 (iii) is one or more polyethyleneglycol (PEG) with the general formula II EQU H-(OC.sub.2 H.sub.4).sub.n -OH (II), PA1 (iv) up to 99 wt. % (wt/wt) of the usual aids and additives.
Although lubricants on basis of soap and namely in the immersion lubrication can be applied relatively trouble-free, the use of lubricants on basis of soap with the presently common centralized lubrication systems causes a number of disadvantages. For example only the disadvantage has to be mentioned that such chain lubricants based on soap are more sensitive towards water hardness, so that they cannot be applied without the use of a complexing agent like e.g. ethylene diamine tetra-acetic acid (EDTA) which can partly mask the hardness of the water. However it is just EDTA, as well as other possible complexing agents, which should be avoided on ground of their ecological disadvantages (relatively difficult degradability in biological purification systems). Similar disadvantages are also shown by use solutions of chain lubricants which are composed on basis of phosphate ester. Therefore presently lubricant concentrates on basis of fatty amines are being applied more and more.
The following publications are mentioned with respect to the specific state of the art as regards lubricant concentrates on basis of fatty amines:
A process is disclosed in D1 for the maintenance of chain shaped bottle conveyors in beverage filling works, especially in breweries, in which the chain shaped bottle conveyors are lubricated with conveyor lubricants on basis of neutralized primary fatty amines and are cleaned with cationic cleaning agents or organic acids. In the process known from D1, conveyor lubricants on basis of neutralized primary fatty amines are used, which preferably show 12 to 18 C-atoms and have an unsaturated content of more than 10%.
The application of an aqueous lubricant solution is known from D2, which solution consists of (A) 0.001 to 1 wt. % on basis of the weight of the aqueous lubricant solution of at least one compound with the formula ##STR1## wherein R.sup.1 is a saturated or an unsaturated, branched or linear alkyl group with 8 to 22 carbon atoms, R.sup.2 is hydrogen, an alkyl group or hydroxyl-alkyl group with 1 to 4 carbon atoms or --A--NH.sup.2,
A is a linear or branched alkyl group with 1 to 8 carbon atoms and A.sup.1 is a linear or branched alkylene group with 2 to 4 carbon atoms, which has a pH-value of 5 to 8, for the lubrication of conveyor belts.
Both the lubricants known from D1 and D2 generally have a poor water hardness tolerance. They tend to react with compounds in the water, particularly with sulphates, bicarbonates, phosphates and carbonates, especially in alkaline water, as well as with other compounds which are present in the water, whereby the reaction products could lead to the development of waste, which block the dosing installation. This leads to the feared "nozzle-blocking" of sieves and spray nozzles of the dosing installation.
Moreover, the lubricants on basis of fatty amines also have an unsatisfactory foam behaviour. Thus, the lubricants according to D2 tend to have an intensive foam formation, which requires afterwards a cleaning of the goods conveyed on the conveyor belt. Other lubricants, like e.g. the composition known from D1, rather tend to a too low formation of foam, which leads to a too fast disappearing of the applied lubricating layer.
It is known from D3 that the application of secondary and/or tertiary amines and/or salts of such amines, whereby the applied compounds essentially are analogous to the amines known from D2, in quantities of 1 to 100 wt. %, if so desired together with the usual diluents, aids or additives, serve as chain lubricants for automatic chain and conveyor belt lubricating installations in the food industry, for the conveyance of plastic objects made of polyethylene terephthalate or polycarbonate. The lubricant compositions known from D3 should not cause stress rupture corrosion thereby, in contrast to standard soap products, when applied with plastic objects, whereby the compositions disclosed according to D3 are particularly suitable for PET and PC-objects. Nevertheless, the lubricant systems known from D3 further exhibit the same disadvantages, which are mentioned above with respect to the lubricants known from D2. The main disadvantage of the lubricants known from D3 is on the one hand the strong water dependence and on the other hand the regularly required system cleaning, which likewise is determined by the kind of compounds in the water. The waste products which are occurring thereby have to be removed. When using lubricants on basis of fatty amines, organic or inorganic acids are applied thereby as cleaner.
In D4 only lubricant concentrates are disclosed on basis of fatty amines and possibly the usual diluents or aids, resp. additives, which are characterized that the composition contains at least one polyamine derivative of a fatty amine and/or a salt of such an amine, whereby the contribution of the polyamine derivative of the fatty amine to the total composition is 1 to 100 wt. %. Although the lubricants known from D4 show a better `clear water solubility`, as well as a more favourable foam behaviour, in comparison with the lubricants known from D2 or D3, also the lubricants known from D4 are possessing certain disadvantages. These include among others a lacking biodegradability. Up to now it has not been possible to biodegrade chain lubricants based on amines in anaerobic purification installations.
Moreover, the compositions described in D4 are detrimental in anaerobic purification installations because of the relatively high use concentration of polyamines.
Nevertheless, its use concentration cannot be lowered just like that, without reducing on the one hand the microbiocide effectiveness to an undesired level, or on the other hand to cancel out the necessary lubricating action. It is possible that an undesired gap of the lubricating film will occur at lower concentrations.
Finally, D5 enriches the state of the art with lubricants containing imidazoline, salts of it or amide, which can occur as intermediate products during the synthesis of imidazoline or as reduction products during the hydrolysis of imidazoline. Although the lubricant concentrates on basis of imidazoline known from D5, respectively its aqueous use solutions, as regards a biocide effect and also as regards a lubricating effect, can completely meet the requirements for appropriate means in the food industry with respect to lubricating, cleaning and disinfecting of feed and conveyance installations, the imidazolines also show certain disadvantages. Thus, under the ecological points of view which have to be taken into consideration nowadays, a biological tolerance and degradability of the lubricant concentrates applied for example in the beverage filling works, which end up in the biological purification, is absolutely necessary in other words for each purification system both an aerobic and an anaerobic degradability in the biological purification installation should be possible. Although this requirement is better met by the chain lubricants based on the imidazoline known from D5 as is the case with some of the chain lubricants based on amine known from D2, D3 or D4, the degradability of the chain lubricants over the whole line need improvement.
Moreover, the chain lubricants according to D3, D4 and also the lubricants according to D5 show a so-called lubricating gap, i.e. the gliding properties in soft water are relatively limited. This means that the friction values in soft water are relatively high. Thus, the known chain lubricants also need to be improved with respect to the lubrication gap.
Although other chain lubricants are known in the state of the art which do not show some of the above indicated disadvantages, however none of the presently known chain lubricants is in the position to fulfil all requirements like water hardness tolerance, aerobic and anaerobic degradability, as well as avoidance of the lubrication gap, to the same extend.
Thus, lubricant compositions are described in EP-A-0 044 458 which practically are free of fatty acid soaps and which contain further a carboxylated, non-ionic tenside and an acylsarcosinate. The pH-value of these products is between 7 and 11 and preferably is within the neutral up to the alkaline range.
DE-A-38 31 448 concerns aqueous soap-free lubricant compositions which are `clear water soluble`, a process for the preparation of these and the use of these lubricant compositions, in particular as lubricants for steel plate conveyors, for the conveyance of glass bottles or polyethylene terephthalate bottles. The, essentially neutral, aqueous lubricant preparations (pH- values within the range of 6 to 8) contain alkylbenzolsulphonate, alkoxylated alkanolphosphate and alkane carboxylic acids, possibly next to the usual intermediate solutions, solvents, defoaming agents and disinfectants.
Nevertheless also the mentioned amine-free products show certain disadvantages, for example they are unfavourable considered from a microbiological point of view, because they create excellent growth conditions for a micro-organism, they only have a limited cleaning power and finally they also show a difficult controllable foam behaviour.
Thus, in view of the above presented and discussed state of the art, it was also an object of the invention to place at the disposal a lubricant concentrate which avoids as far as possible the disadvantages of known lubricant preparations according to the state of the art with respect to the water hardness tolerance, the toxicity of the compounds in the lubricant as well as the friction values in soft water. At the same time the lubricant concentrate should display a high substantivity, i.e. an improvement of the moistening power, a lower friction value generally, a balanced foam behaviour, a good and `clear water solubility`, a good cleaning effect and an excellent biocide effect. Herein the concept `clear water solubility` in water means the insusceptibility of the lubricant components against anions in natural waters, like sulphate, bicarbonate and the like. For example, if the `clear water solubility` of a lubricant composition is not very marked, the composition could react with the compounds in the water during a longer standstill of the installation, for example during the course of a weekend. The resulting waste and turbidity in the use solutions of the lubricants lead in the short or medium term to clogging up of the filters and nozzles of the conveyor lubricating systems.